Girder, and truss variable in length made therefrom



April 10, 1956 G PLElTGEN ET AL 2,741,343

GIRDER, AND TRUSS VARIABLE IN LENGTH MADE THEREFROM 2 Sheets-Sheet 1 Filed Sept. 11, 1952 A r/75f M Azas lai la a April 10, 1956 M. G. PLEITGEN ET AL GIRDER, AND TRUSS VARIABLE IN LENGTH MADE THEREFROM 2 Sheets-Sheet 2 Filed Sept. 11, 1952 INVENTOPS fia'x 6: 7 /8/6081) awn 70.11 M /azzs Pa/eal life/r) United States Patent GIRDER, AND TRUSS- VARIABLE IN'LENGTI-L MADE THEREFROM Max G. Pleitgen, Dusseldorf, and Ernst M. Klaus, Hiltlen, Germany, assignors to Betonbau Geseilschait mi: beschrankter Haftung, Dusseldorf, Germany Application September 11', 1952:, Serial No. 309,619

IZClaims. (Cl. 189-37).

The present invention relates to floor. beams, trusses, or. the. like. which are adjustablein length. and, to; this end, comprise two or more lattice girders movable, relative to each other. In order to connect, such lattice girders with each other and to hold the same in their respective adjusted positions, it is known to provide the, top chord with a plurality of spacednbores, through which connecting bolts are passed, whereas clamps or thelike,

are arranged at. thebottom chord. Thedrawback offthis type of beam or truss consists primarily in that the con: necting bores are subjected-to shearingstressesand that, furthermore, the longitudinal relative adjustment of the girders is limited by the distance between the bores through which, the connectingbores, are passed, so that a fine adjustmentof such beams or trusses is notpossible.

It, is, therefore, anobject of this invention to provide When the beam or truss is drawnoutfrom its shortest or starting length to a greater length, itwill be evident that each end, of thebeam or truss has a width and thus a supporting surface which, correspondsto the width of the horizontal arm of one angle only. In other words, the supportingwidth at the, endportions of'the beam or truss is only half as wide as. the supporting width between said' end portions. 7

It is, therefore, still another object of this invention to provide means which. will make it, possible also with an improved beam or truss according to the invention to obtain a full supporting surface at the ends of such beam or truss, which is of particular importance when butt joints are desired or hollow bodies such as concrete hollow bodies are to be installed.

These and other objects and advantages of theinyen: tion will appear more clearly from the followingspecifi cation in connection with the accompanying drawings, in, which:

Fig. I is a side view of a bearnor truss, construction according to the invention.

Fig. 2 is a cross, section through Figure 1- taken along the line Il-l'l thereof;

Fig. 3 is. a side view of a beam or trussaccording to the invention provided with an auxiliary angle.

Fig. 4 illustrates a vertical section through Figure 3 taken along the line- IVIV thereof but on a somewhat larger scale than the latter.

Figure 5'represents a top view-of Figure 3'.

Fig. 6 shows some further detailsof a beam or trussaccording to the invention.

Referring now to the drawings indetail and Figs: 1

2,741,343 Patented Apr. 10, 1956 and, 2 thereof, inpa-rticular, the. structure shown therein rep ents a beam, or truss according to thev invention. This beatn or truss is composed of two lattice girders e h. f. hich. omprises n upper angle 1 a lower anglezb', and braces or rods, 3b of round or similar mari ,v h h race or rods are. connec e preferably welded; to said angles 1b and 2b. According to the present inventiomeafih. lattice girder is. provided with a flat metal rail 5b the upper edge of which is substantially parallel to and'spaced from the lower edge of the verticalleg of the adjacent angle 1b so that a long slot 4b is formed. The rails 5b are held in their spaced parallel positions with regard to the vertical legs of the angles 1b by. connecting, preferably welding, said rails to the braces 3b.

In order to assemble the truss, the two girders are placed back, to back so that the upper horizontal surfaces of the angles 1b are flush with each other, whereupon bolts are passed through the slots 4b from the outside of one girder, while nuts are placed on said bolts from.

the outside of the other girder. While such bolts may be. of any standard type, it is advantageous to employ connecting bolts 12 with ahammer shaped head 13 as shown in Fig. 2. Thewidth of the head. 13 is slightly less than the width of slot 4b, so that the bolt with its head 13, may be passed from one side of the truss through slot 4b. Below the headlj on the bolt 12' there may be provided a short neck portion 14 of square cross section which is only slightly narrower than the slot lb. In order to pass such bolt 12' from the left side (as viewed in Fig. 2) with head 13 and neck 14 of the truss, through slot'4, the head 13 is first brought into register with slot 4, whereupon the head 13, square 14 and bolt 12 can be passed through slot 4. The bolt 12 is passed through slot 4b to such an extent thatthe square 14' will clear, slot lb,

i; with regard to Fig. 2 will be on the right hand side ofthe right hand bar 512'. Then the bolt 12 is turned by and the bolt 12 is retracted as far as it will go so that the neck 14 will be in the slot 4b. Now the nut 15 is applied, and due to the fact that neck 14 just fits into the slot 4, the bolt 12 cannot rotate while the nut is being tightened. On the other hand, if it is desired for some reason, to take out the bolt 15, itis not necessary completely to unscrew the nut 15 but it will sufice merely to loosen the nut 15 to such an extent that the neck 1'4 can be'pushedout of slot 4b towards the side where the hammer head 13 is located, whereupon head 13 can be rotated by 90 and the bolt with head can be completelywithdrawn from the slot 4b.

The two lower angles 25 are held back to back by clamping means. More specifically, according to Figs. 1 and 2, bolts 17 (one only beingshown) with book shaped head 18 are provided which head catches behind the horizontal arm of the adjacent angle'2b. Each bolt 17 extends through a sleeve 21 which is somewhat shorter than the total width of the horizontal arms of both angles 2b.

A clamping disc 19 with a hook 2-8 catching behind the adjacent arm of the. other angle 2b is adapted to be tightened by a nut'l'lb' so that both angles 2b are clamped together.

Before'tightening the nuts 15 and 17b, the girders are preferably-moved-rel'ative to each other to suchan extent that the truss will have at least the approximate desired length whereupon the. said nuts are tightened and the girders are firmly held together. Should any further relative adjustment of the girders become necessary when the-beam is being installed, this can easilybe eifected afterloosening the nuts 15, 17b.

The thickness of the rails 5b is preferably selected so that the outer vertical surfaces thereof are flush with the corresponding outer vertical surfaces of the angles so to each other is fully taken over by the rails 'Sb.

total thickness of the. rails Sb'maydiffer from the total thickness of the vertical legs of the angles 1b.

In such an instance, shims, washer plates or the like may be used, in order to cause the bolts 12 evenly to press against 7 each other both. the angles 11) and the respective rails b.

It should be noted here, that the bolts 12 with the nuts 15 merely serve the purpose of preliminarily holding the girders in their respective adjusted positions until the nuts are properly tightened, whereupon the task of preventing any material movement of the girders relative In other words, the friction areas between the girders have been increased by the rails 5b to such an extent that this friction more than sufiices safely to hold the girders in their relative adjusted positions. Thus, in contrast to adjustable beams or trusses heretofore known, the bolts 12 in the arrangement of the present invention are not subjected to shearing stresses. Consequently, only a few bolts will sufiice to hold the girders together. Thus, for

to the invention of a span width of 14.74 feet and subjecting the same to a load of 1.2 tons, only two bolts at each the upper chord and the lower chords will sufiice, when the width of the upper and lower angle legs and the width of the rails is approximately 0.118 inch, while the overlapping of the girders is 6.56 feet and the distance between the bolts is about 3.28 feet.

. It should be noted that due to the fact that the beam or truss according to the present invention has a continuous slot, easy and fine adjustment of the girders at the building site is possible without having to withdraw the bolts from the girders and without being limited to a predetermined step-wise adjustment; Also the bolts can easily be moved to anydesired place.

The girders according to the invention have a relatively low weight and can easily be handled and installed. For supporting ceilings, roofs and the like, the ends of the individual girders may be provided with hearing plates 10b (similar to plate 10 of Fig. 5) so that full supporting width, particularly when dealing with butt joints or when mounting hollow'bodies, auxiliary angles as shown in Figs. 3 to 5 may be used.

According to Figs. 3 to'5 a plurality of auxiliary angles 32 are welded tobrackets 33 which latter have fingerlike extensions 33a that extend through the slot 34 and rest against the lower surface of the horizontal arm of the angle 35, while the lower part of the bracket rests against the rail 36 according to the invention. The space between two adjacent auxiliary angles is closed by inserting a U-rail 37. As will be seen from Figs. 4 and 5, the

width of the angle 32 preferably, although not necessarily,

equals the width of the U-rail 37. Thus, considering the width of U-rail 37 plus the Width of angle 32 as the total width of the auxiliary angle or the full supporting width of the truss, it will be noted from Fig. 5 that, unless the space between two adjacent angles 32 is long enough to.

allow the insertion of another rail 36, the total supporting width between two adjacent angles32 is smaller by the width of the-angle 32, This, however, is immaterial from a practical standpoint inasmuch as in at least 90% of all possible instances, the supporting width of a truss section between two adjacent angles 32, which width is I composed of the width of the angle plus the width instance, when employing a two girder truss according of the U-rail 37, will fully suffice.

isnecessary, this can be obtained without difficulty by inserting a shorter angle similar to angle 32 between two adjacent angles 32.

If desired, the respective contacting surfaces of the rails,.the upper and/or lower chord elements may. be knurled, grooved, corrugated or the like as shown on a larger scale at 47, 48 of Fig. l7 so that, when pressing these elements together, the elevations of one contacting surface will enter the depression of the other contacting surface so that the contacting surfaces will actually interlock. This will definitely exclude any relative accidental movement between said surfaces.

Another advantage of this interlocking arrangement consists in that the overlap of the girder need be only /3 as large as heretofore in order to obtain the necessary friction. The bend-through, as the practice has shown, will be materially'less in view of the complete immovability of the respective chord angles.

While the girders illustrated in the drawings and described in the specification are lattice girders, it is, of course, understood that the invention is also applicable to other type girders, such as box girders, plate girders, and the like.

It is also to be understood that the present inventionis by no means limited to theparticular constructions shown, 7 in the drawings but also comprises any modifications withto serve as part of a mold for building ceilings, floors and the like, which comprises in combination, a first longitudinal element forming the upper chord of said girder, oneend of said element'including an extension having its upper surface flush with the upper surface of said element and'having a width considerably wider than thewidth of said element, a second longitudinal element spaced from said first longitudinal element and forming the lower chord of said girder, zig-zag shaped connecting means fixedly and permanently interconnecting said first and said second longitudinal elements and maintaining the same in spaced relationship with regard to each other,

said second longitudinal member being at least approxiand the like, which comprises in combination, an angle having a substantially horizontal and a substantially vertical portion and forming the upper chord of said girder, one end of said element including an extension having its upper surface fiush'with the uppersurface of said element and having a width considerably wider than the width of said element, a longitudinal member spaced from and substantially parallel to said angle, said longitudinal member forming the lower chord of said girder, brace means welded to said angle and said longitudinal mem-' her and maintaining the same in spaced relationship with regard to each other, and a rail member having one of.

its longitudinal surfaces arranged in the same plane as one ofthe longitudinal surfaces of said vertical portion,

said rail member being substantially parallel tothe lower edge of said vertical portion but slightly spaced therefrom by a distance suflicient to allow the passage of a bolt between said lower edge and said rail for connecting a said girder to a similar girder.

3, A girder according to claim 1, in which one end of In special instances, ,however, where the full supporting width of the truss said first longitudinal element is, provided with a substantially horizontal end snpportihgplate having-awidtlr nearly twice the Width of said first'longitudinabelement.

4. A girder for use in connection with trusses, beams or the like that are adapted to be adjusted in lengthand to serve as part of a mold for building ceilings, floors and the like, which comprises in combination, a first angle having a substantially horizontal'andasubstantia-lly vertical portion forming the upper chord ofsaid girder, an auxiliary angle having a substantially horizontal and a substantially vertical portion andhaving a length materially shorter than the length of said first angle, said first angle and said auxiliary angle having their vertical portions arranged so that their backs face each other and that the upper surfaces of 'said horizontal portions are substantially flush with each other, a second angle vertically spaced from said first angle and substantially parallel to said first angle, a rail substantially parallel to and vertically aligned with the vertical'portion of said first angle, said rail being spaced from saidlast mentioned vertical portion so as to allow passing a connecting bolt between said last mentioned vertical portion and said rail, connecting means interconnecting said first and second angles and said rail and maintaining the same in spaced relationship with regard to each other, and'means interconnecting said first angle and said auxiliary angle.

5. A girder for use in connection with trusses, beamsor the Idea that are adapted to be adjusted in length and to serve as part of a mold for building ceilings, floors and the like, which comprises in combination, a first angle forming the upper chord of the girder and'having' a horizontal and a vertical longitudinal portion, a second angle vertically spaced from said first angle and forming the lower chord of said girder, a rail substantiali i parallel to the lower edge. of said vertical portion of said first angle and spaced therefrom so as to allow passing a connecting bolt between said last+mentioned vertical portion and said rail for'connecting, said girder to a similar girder, connecting means interconnecting said;

first and second angles and maintaining thesameiinrspaced relationship with regard to each other, bracket means connected to an end portion of said rail and having an extension extending through the space between said first angle and said rail and resting against thelower surface ofasaid horizontal portion of said first angle, an auxiliary angle having a horizontal and a vertical portion .andibeing connected to said bracket means, the horizontal. portion of said auxiliar angle being substantially flush with the horizontal portion of said first angle, the vertical portion of said auxiliary angle beingspaced by a predetermined distance from the vertical portion of said first angle, and U-shaped rail means having a width substantially corresponding to said predetermined distance and being inserted between the vertical portion of said first angle and the vertical portion of said auxiliary angle sothat the legs of said U-shaped rail'means point downwardly and the upper surface of the portion between said legs is substantially flush with the upper surface of the horizontal portions of said first angle and said auxiliary angle.

6. A truss, beam or the like adjustable in length and to serve as part of a mold for building ceilings, fioors, and the like, which comprises in combination, a first longitudinal member having a horizontal portion and a vertical portion, a second longitudinal member having a horizontal portion substantially fiush with said first horizontal portion and also having a vertical portion of substantially the same height as said first mentioned vertical portion, said vertical portions being arranged in abutment with each other, a first rail and a second rail substantially parallel to the lower edge of each of said vertical portions and respectively slightly spaced therefrom by a distance sufiicient to allow passing connecting bolt means between said rails and the adjacent edges of said vertical portions, said rails being arranged in abutment with each other with the abutting surfaces thereof arranged in' substantially" the same plane as'tlieabutting surfaces of said vertical portions, a' third and a fourth longitudinal member at'least nearly parallel to said firstmentioned two rails andarranged in abutment witheach other while having their abuttingsurfaces located in sub stantially the same plane as the abutting'surfaces of said first and second longitudinal members, first bracing means interconnecting said first and said'third longitudinal members' and said first rail and maintaining the same in relative spaced relationship with regard to each other, second bracing means fixedly interconnecting said second and said fourth longitudinal members and said second rail and maintaining the same in spaced relationship with regard to each other, connecting bolt means extending between said first and second longitudinal members and said first and second rails, said'first and said second longitudinai members being movable relative to each other in an infinitely variable manner as a unit with the rails and bracing means connected thereto, and nut means cooperating with said bolt means for respectively clamp ing said first and second longitudinal members'and said rails together in any desired adjusted position.

7. In-combination: a first girder; a second girder; said girders being mounted in back to back abutting arrangement; each of said girders comprising a first longitudinal member forming the'upper chord of the respective girder, a longitudinal rail substantially parallel to and slightly spaced from said first longitudinal member sufiicient to allow passing bolt means between said longitudinal morn-- her and said rail, a second longitudinal member spaced from said rail, and brace means welded to saidfirst and second longitudinal members and said rail and maintaining the same in spaced relationship with regard to each other; said two girders being adjustable relative to each other in an infinitely variable manner, and clamping means" including bolt means extending between said first longitudinalmembers and said'rails and adapted to interconnect the upper portions of said girders in any position of said girders relative to each other, said clamping meansbeing arranged at a level below the uppermost surface of" said first longitudinal member.

8. An arrangement according to claim 7, in which the clamping means include bracket means adapted to engagesaid second longitudinal members and also include bolt members extending through said bracket means and adapt ed to clamp the same together, to thereby also clamp said" second longitudinal members against each other.

9. A truss, beam or the likewhich comprises in com-- bination: a first girder, a second girder, each of said girders including a first angleforming the upper chord of" the respective girder and having a horizontal and: a vertical longitudinal portion, a second angle vertically spaced. from said first angle and forming the lower chord of the respective girder, a rail substantially parallel to the lower edgeotsaid vertical portion and spaced therefrom so as to allow passing a connecting bolt through the space between said vertical portion and said rail, connecting means interconnecting said first and second angles and maintaining the same in spaced relationship with regard to each other, bracket means connected to an end portion of said rail and having an extension extending through said space and resting against the lower surface of said horizontal portion, an auxiliary angle connected to said bracket means and having a horizontal portion substantially flush with the horizontal portion of said first angle and having a vertical portion spaced by a predetermined distance from the vertical portion of said first angle, and U-shaped rail means having a width slightly less than said predetermined distance and being inserted between said first angle and said auxiliary angle; and connecting bolts extending through said space for connecting the upper portions of said girders to each other; and means mounted on said second angles of said girders for clamping said second angles against each other.

the construction of concrete floors, ceilings and the like, which comprises in combination: two'girdcrs adjustable relative to each other in an infinitely variable manner;

each of said girders comprising a first angle forming the upper chord of the girder and having a horizontal and vertical longitudinal portion, a second angle substantially evenly vertically spaced from said first angle and forming the lower chord of said girder, a rail substantially parallel to the vertical portion of said first angle and spaced therefrom by a distance just suflicient to allow the passage of a bolt through the slot formed between said first angle and said rail, and zig-zag shaped rod means directly and fixedly interconnecting said rail, said first' girder, and said second girder; and cleansing means including bolt means extending through the slots defined '7 by said'first angle and said rail of each of said girders,

said clamping means being arranged below the uppermost surface of said first angle so as not to interrupt the uppermost surface of said first angle, said clamping means also comprising nut means threadediy engaging said'bolt means and movable to press said first angles together and simultaneously to press said rails together to thereby considerably increase the friction between said two girders and to cause said rails to take part'in the absorption of the load. 7 I

11. An extensible truss, beam or the like adjustable in length for use as a member of a mold in connection ,7 V with the construction of concrete floors, ceilings and the like, which comprises in combination: two girders adjustable relative to each other in an infinitely variable manner'; each of said girders comprising a first angle forming the upper chord of the girder and having a horizontal and vertical longitudinal portion, a second angle substantially evenly vertically spaced from said first angle and forming the lower chord of said girder, a rail substantially parallel to-the vertical portion of said first angle and spaced therefrom by a distance just sufficient to allow the passage ,of' a bolt through the slot formed between said first angle and said rail, and zig-zag shaped rod means directly and fixedly interconnecting said rail, said first girder, and said second girder; and clamping means including bolt means extending through the slots defined by said first angle and said rail of each of said girders,

' said clamping means being arranged below the uppermost surface of said first angle so as not to interrupt the uppermost surface of said first angle, said clamping means also comprising nut means threadedly engaging said bolt means and movable to press said first angles together and simultaneously to press said rails together to thereby considerably increase the friction between said two girders and to cause said rails to take part in the absorption of the load, each of said girders having one end thereof provided with a supporting arm having its upper surface substantially flush with the upper surface of the girder 8 v connected thereto and being provided with rounded corners to facilitate the removal of the respective girder from the poured concrete adjacent said girder.

12. An extensible truss, beam or the like adjustable in length for use as a member of a mold in connection with the construction of concrete floors, ceilings and the like, which comprises in combination: two girders adjustable relative to each other in an infinitely variable manner; each of said girders comprising a first angle forming the upper chord of the girder andhaving a horizontal and vertical longitudinal portion, a second angle substantially evenly vertically spaced from said first angle and forming the lower chord of said girder, a rail substantially parallel to the vertical portion of said first angle and spaced therefrom by a distance just suificient to allow the passage of a bolt through the slot formed between said first angle and said rail, and zig-zag shaped rod means directly and fixedly interconnecting said rail;

said first girder, and said second girder; clamping means including bolt means extending through the slots defined by said first angle and said railof each of said girders, said clamping means being arranged below the uppermost surface of said first angle so as not to interrupt the uppermost surface of said first angle, said clamping-means also comprising nut means threadedly engaging said bolt means and movable to press said first angles together and simultaneously to press said rails together to' thereby considerably increase the friction between said two gird-.

ers and to cause said rails to take part in the absorption of the load, and additional clamping means for clamping said second angles together, said additional clamping means including a sleeve having a length slightly longer than the maximum width of said second angles, a bolt 7 extending through said sleeve and having an L-shaped head extending over a portion of one of said second angles, L-shaped washer means supported by said bolt and engaging a portion of the other one of said second angles, and nut means clamping said washer means and head against the ends of said sleeve and over adjacent portions of said second angles.

References Cited in the file of this patent UNITED STATES PATENTS 

